1. Field of the Invention
The present invention relates to a circuit interrupting apparatus and, more particularly, to a circuit interrupting apparatus for medium- and high-voltage circuit isolating devices having operations counters and methods of forming and using such circuit interrupting apparatus associated therewith.
2. Description of the Related Art
Circuit isolating devices such as fuse cutouts, disconnecting switches, and power fuses are adapted to be periodically opened to provide necessary service, such as for fuse replacement or service to power lines. Conventionally, such circuit isolating devices include a ring-like conducting part and a hook-like conducting part which are relatively movable between a contacting position to establish a closed circuit through the device and a separated position to establish an open circuit through the device.
When it is necessary to open the circuit isolating device when it is carrying load current, an arc is drawn between the two conducting parts, which is likely to damage any components which are contacted by the arc. Also, where other adjacent circuits are involved, there is a risk that the drawn arc may jump to another circuit, causing a fault in the other circuit. Still further, there is a risk that the drawn arc can jump an operator, causing some type of injury.
To minimize the risks and dangers associated with the opening of such circuit isolating devices, a specially designed portable circuit interrupting apparatus has been developed as described, for example, in U.S. Pat. No. 2,816,984 by Lindell titled “Circuit Interrupter Construction” and in U.S. Pat. No. 2,816,985 by Lindell titled “Circuit Interrupting Means.” This apparatus typically comprises a rod-like terminal which enters the ring-like conducting part of the isolating device and a second terminal which loops about the hook-like conducting part. The interrupting apparatus is mounted at the upper end of an elongated line pole.
In use, the operator initially lifts the apparatus to an elevated position adjacent the isolating device while holding the lower or proximal end of the line pole, and the operator then swings the interrupting apparatus into engagement with the isolating device so as to bring the two terminals of the interrupting apparatus into proper contact with the two conducting parts of the isolating device. The interrupting apparatus of the type described above, and as illustrated and described in the above-referenced patents, should be carefully manipulated during its initial engagement with the isolating device so that the two terminals properly engage the two conducting parts of the isolating device. This typically requires the hook engaging terminal of the interrupting apparatus to initially engage the hook-like conducting part of the isolating device. The interrupting apparatus is then swung laterally so that the ring engaging terminal of the interrupting apparatus enters the ring-like conducting part of the isolating device.
Upon then pulling downwardly on the line pole, the operator is able to separate the two conducting parts of the isolating device to open the circuit so that the current then flows through a shunt circuit which is located in the interior of the interrupting apparatus. The interrupting apparatus further has a shunt circuit interrupter which opens the shunt circuit inside the apparatus so that the resulting arc is confined to the interior of the apparatus. Next, the interrupting apparatus is disconnected from the two conducting parts of the isolating device. A resetting latch is then engaged to allow the interrupting apparatus to be reset for the next use.
Often it is desirable to keep track of the number of interrupting apparatus operations, and thus the number of circuit isolating devices serviced, in order to analyze operator productivity or to facilitate maintenance based on the number of operations rather than length of time the interrupting apparatus is in the field. It is, however, difficult to accurately keep track of the number of operations performed by each interrupting apparatus. It has been recognized that an operation counter can be used to count the number of operations. For example, U.S. Pat. No. 6,300,585, by Nicolai titled “Operation Counter for a Circuit Interrupter,” describes an operation counter used to count the number of operations of a circuit interrupter in order to determine the operating life of the circuit interrupter and to determine a maintenance schedule to be applied to the circuit interrupter. The operation counter is responsive to contact with an arc-suppressing member and is positioned on or within an exhaust control portion of a circuit interrupter. Applicants have recognized that counters such as that described, however, are prone to excessive wear because part of the counter mechanism is in contact with arc-interrupting components or shunt-interrupting circuits which are subject to the wear and tear or other forms of degradation caused by arcing resulting from the circuit interrupting operation. Applicants therefore also recognized a need for an interrupting apparatus which can count the number of operations performed by each circuit interrupting apparatus that does not require direct interface with shunt-interrupting circuit components. Additionally, there are many circuit interrupting apparatus deployed in the field which do not have an operation counter. Applicants also further recognized a need for an operation counter that can be easily and inexpensively retrofitted to existing circuit interrupting apparatus to provide a count of the number of operations performed by the operator on an isolating circuit device.
Additionally, though such counters can be used to show a possible representation of the wear and tear on the circuit interrupting apparatus, such counters record operations regardless of the amperage of the circuit being interrupted. Though operator productivity is not a function of the amperage of the circuits repaired by the operator and a rough representation of component fatigue can be deduced from a raw count of the number of operations, high amperage operations cause much more wear and erosion than medium amperage operations which cause more wear and erosion than low amperage operations. Applicants still further recognized a need for a counter that can record total operation counts along with operation counts related to various categories of amperage interrupted by the interrupting apparatus to be used to formulate a maintenance or inspection schedule.